methanol intoxication - diagnosis and management
DESCRIPTION
Emergency ToxicologyTRANSCRIPT
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Methanol Intoxication;
Diagnosis and Management
Al i Haedar
Clinical Lecturer & Emergency Physician
Department of Emergency Medicine
Faculty of Medicine – Universitas Brawijaya
Saiful Anwar General Hospital
Indonesia
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Introduction
• Methanol is odorless and colorless liquid
• Found in:
– deicing solutions,
– windshield washer fluid, – paint removers,
– solvents,
– chafing dish heat sources, and
– other commercial products
• Alcoholics sometimes mix it and other liquids
(i.e., energy drink and soda drink) into ethanol
to get extra effect
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Introduction
• Most methanol intoxication cases in Indonesia
are secondary to consumption of mixed liquors
• Alcohol containing liquors in Indonesia, mostlyproduced by home industries
• Very cheap; only USD1 (IDR12,500) per glass
(in some area)
• Emergency doctors may fail to recognize of
patients with ethanol dependence
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Prevalence
• 35 cases in year 2010 in ED Saiful AnwarGeneral Hospital Malang
• 17 death cases within 6 hours admission
• >8 million Americans are believed to be
dependent on alcohol, and up to 15% of the
population is considered at risk
• In some studies, more than 50% of all trauma
patients are intoxicated with ethanol at the time
of arrival to the trauma center
ATSDR. Methanol toxicity. Agency for Toxic Substances and Disease Registry. Am Fam Physician. Jan 1993;47(1):163-71
Aufderheide TP, White SM, Brady WJ, et al. Inhalational and percutaneous methanol toxicity in two firefighters. Ann EmergMed. Dec 1993;22(12):1916-8
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Toxicity
• Ingestion remains the primary route of exposure.
• Methanol itself is nontoxic; toxicity arises from its
metabolite, formic acid (formate).
• Normal methanol blood level endogen is 0.05
mg/dL
• Asymptomatic individual have peak level <20
mg/dL
• Level >50mg/dL serious poisoning (CNS and eye
problems)
• Fatal case with level >150-200mg/dL
Bronstein AC, Spyker DA, Cantilena LR Jr, Green JL, Rumack BH, Heard SE. 2007 Annual Report of the American
Association of Poison Control Centers' National Poison Data System (NPDS): 25th Annual Report. Clin Toxicol (Phila). Dec
2008;46(10):927-1057. [Medline].
Barceloux DG, Bond GR, Krenzelok EP, et al. American Academy of Clinical Toxicology practice guidelines on the treatment
of methanol poisoning. J Toxicol Clin Toxicol. 2002;40(4):415-46
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Methanol
Toxicity
N Engl J Med 2009;360:2216-23.
• Methanol itself is nontoxic; toxicity arisesfrom its metabolite, formic acid (formate)
• HAGMA + Blindness!
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Clinical Features
The symptoms of methanol poisoning may not appear for
up to 12 to 18 h after ingestion because of the time it takes
for methanol to be metabolized to it toxic metabolites.
• GI tract : – nausea,
– vomiting, – abdominal pain.
• CNS : – headache,
– confusion,
– decreased level of consciousness.
• Ocular : – retinal oedema and
– hyperaemia of the disk,
– decrease of visual acuity.
• Metabolic acidosis
– Kusmaul type of breathing
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Diagnosis
Based on
• history
• the characteristic clinical features
• the presence of wide anion gap
metabolic acidosis and osmolar gap
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Management• 1. ABCs / supportive care
– Intubation with RSI method, controlled the ventilation, manage thecirculatory
• 2. Prevent metabolism of methanol – Ethanol IV
– Ethanol via NG tube
* Ethanol’s affinity for enzyme is 10-20 times that of methanol
– Fomepizole* Fomepizole has affinity for alcohol dehydrogenase 8000 times that of
ethanol
• 3. Enhance removal of formic acid – Folate 1mg/kg IV q4h
• 4. Correct acidosis
– Dialysis – Sodium bicarbonate
• 5. Remove methanol – Dialysis
Kosten TR, O'Connor PG: Management of drug and alcohol withdrawal. N Engl J Med 348: 1786, 2003.
Jeffrey Brent, M.D., Ph.D. Fomepizole for Ethylene Glycol and Methanol Poisoning. N Engl J Med 2009;360:2216-23.
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Treatment of Methanol Poisoning
AgentIndications
for treatment
Treatment
Methanol
Methanol >20 mg/dL
Ingestion > 0.4 mg/kg
History, symptoms
Suggestive of poisoning
Ethanol IV:
Loading dose: 10% ethanol in D5W at 10
mL/kg over 30 min*
Infuse:10% ethanol in D5W at1.5mL/kg per h
to maintain ethanol level at 100-150mg/dL°, or
Ethanol Oral:
loading dose: 0.8-1 mL/kg PO of 95% ethanol
in 6 oz of orange juice
over 30 min
Average maintenance doses (PO/IV): 0.15
mL/kg/h PO of 95% ETOH
Fomepizole 15mg/kg over 30 min,
Then 10mg/kg q12h X 4 doses
Folinic acid 1mg/kg IV (max 50mg) q4h
NaHCO3 1mEq/kg IV for severe acidosis
Kosten TR, O'Connor PG: Management of drug and alcohol withdrawal. N Engl J Med 348: 1786, 2003.
Jeffrey Brent, M.D., Ph.D. Fomepizole for Ethylene Glycol and Methanol Poisoning. N Engl J Med 2009;360:2216-23.
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Effects of Alcohol
• Ethanol’s affinity for enzyme is 10-20 times that of methanol
• Alcohol competes with Methanol
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N Engl J Med 2009;360:2216-23.
Effects of
Fomepizole
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Dialysis
Indication for dialysiswith methanolintoxication:
1. Sign of visual or
CNS dysfunction2. Peak methanol
level >20 mg/dL
3. pH< 7.15
4. History of
ingestion >30 mLmethanol
Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli, 2004, 6 th ed,section 14,page 1067
Ekins BR, Rollins DE, Duffy DP, et al: Standardized treatment of severe methanol poisoning with ethanol and hemodialysis. West J Med1985 Mar; 142:337-340
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Facts
• We do NOT have ethanol 20% or 40%
solution in Indonesia
• We administered liquor like Chivas Regal
(the alcohol concentration ~ 40%)
• Alcohol 70% + water + contamination of
bacteria & yeast = METHANOL !!!
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How do we administer ethanol?
IV:
• More benefitial
• More rapid action
• No ethanol IV preparation in Indonesia• Do not use oral ethanol preparations IV!!!
NGT:
• 40% ethanol containing liquor mix with D5%(equal volume)
Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli,2004, 6th ed,section 14,page 1067
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Charcoal?
• Because toxic methanols are absorbed so
rapidly, gastric emptying is unlikely to be of
benefit, and there is no evidence to support its
routine use.
• Activated charcoal is not indicated for methanol
ingestions, although if co-ingestion of an agent
known to adsorb to charcoal is suspected, it
may be given for this reason.
Toxicology & pharmacology, Emergency Medicine, a Comprehensive study guide, JE Tintinalli,2004, 6th ed,section 14,page 1067
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Challenges
• ? medico-legal ethic
• ? components other than alcohol
inside the liquor
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Differential Diagnosis
• High Anion Gap Metabolic Acidosis
M methanol
U uremia
D DKA, ketonesP paraldehyde
I INH, Iron
L lactate
E Ethanol, Ethylene glycol
S salicylates
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Prognosis
• Mortality >80% if present with
either:
– Severe metabolic acidosis (pH <7)
– Seizures
– Coma
• Mortality <6% in absence of above
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Discussion
• We diagnose patient with methanol
intoxication based on the history and
clinical presentation.
• The most initial symptom of methanol
intoxication is visual impairment, seen in
50% of patients
• This symptom will manifest around 2 days
after consumption
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Discussion
• Many hospitals are not supported
with the test of ethanol, methanol,
or other alcohol level.
• We diagnose patient with methanol
intoxication based on the history
and clinical presentation, with high
anion gap acid base analyze.
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Discussion
• Prognosis is correlated with the degree
of metabolic acidosis (and the quantity
of methanol ingested); more severe
acidosis confers a poorer prognosis.
• Direct correlation exists between the
formic acid concentration and the
pathologies
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Summary
How to improve the outcomes?
• Early recognition
• Aggressive treatment by supportingairway & breathing
• Inhibiting metabolism of methanol
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Thank You